Members submitted comics to the CCA, which screened them for adherence to its Code, then authorized the use of their seal on the cover if the book was found to be in compliance. At the height of its influence, it was a de factocensor for the U.S. comic book industry.

By the early 2000s, publishers bypassed the CCA and Marvel Comics abandoned it in 2001. By 2010, only three major publishers still adhered to it: DC Comics, Archie Comics, and Bongo Comics. Bongo broke with the CCA in 2010. DC and Archie followed in January 2011, rendering the Code completely defunct today.

Like the previous code, the CCA prohibited the presentation of "policemen, judges, government officials, and respected institutions … in such a way as to create disrespect for established authority." But it added the requirements that "in every instance good shall triumph over evil" and discouraged "instances of law enforcement officers dying as a result of a criminal's activities." Specific restrictions were placed on the portrayal of kidnapping and concealed weapons. Depictions of "excessive violence" were forbidden, as were "lurid, unsavory, gruesome illustrations." Vampires, werewolves, ghouls and zombies could not be portrayed. In addition, comics could not use the words "horror" or "terror" in their titles. The use of the word "crime" was subject to numerous restrictions. Where the previous code had condemned the publication of "sexy, wanton comics," the CCA was much more precise: depictions of "sex perversion", "sexual abnormalities", and "illicit sex relations" as well as seduction, rape, sadism, and masochism were specifically forbidden. In words echoing the Hollywood Production Code, love stories were enjoined to emphasize the "sanctity of marriage" and those portraying scenes of passion were advised to avoid stimulating "lower and baser emotions."

In his introduction to Archie Americana Series Best of the Fifties, editor Victor Gorelick reminisced about the Code, writing, "My first assignment, as a new art assistant, was to remove cleavages and lift up low cut blouses on Katy Keene."[4] He also wrote of Archie artist Harry Lucey that, "His sometimes suggestive storytelling – and he was one of the best – almost cost him his job. When his pencilled stories came in, the characters were dressed on one page only. The inker, a woman by the name of Terry Szenics, would have to clothe them on the remaining pages."[5]

Although the CCA had no official control over publishers, most distributors refused to carry comics that did not carry the seal.[6] However, two major publishers of comics – Dell Comics and Gold Key Comics – did not display the seal because their output was subject to a higher authority - their licensors.[7]

Some publishers thrived under these restrictions, while others adapted by canceling titles and focusing on Code-approved content, and still others went out of business. In practice, the negative effect for not having CCA approval was lack of distribution from comic book wholesalers, who, as one historian observed, "served as the enforcement arm of the Comics Code Authority by agreeing to handle only those comics with the seal."[8]

Publisher William Gaines believed that clauses forbidding the words "crime", "horror", and "terror" in comic book titles had been deliberately aimed at his own best-selling titles Crime SuspenStories, The Vault of Horror, and Tales from the Crypt.[9][10] These restrictions, as well as those banning vampires, werewolves, and zombies, helped make EC Comics unprofitable; all of its titles except Mad were canceled in the year following the CCA's introduction, and attempts by EC to launch Code-friendly replacement titles were unsuccessful. Mad itself survived because Gaines had converted the publication to a magazine format, to which the Code did not apply.

Wertham dismissed the Code as an inadequate half-measure.[11] Comics analyst Scott McCloud, on the other hand, later commented that it was as if, in drawing up the code, "the list of requirements a film needs to receive a G rating was doubled, and there were no other acceptable ratings!"[12]

In one early confrontation between a comic-book publisher and Code authorities, EC Comics' William Gaines reprinted the story "Judgment Day", from the pre-Code Weird Fantasy #18 (April 1953), in Incredible Science Fiction #33 (Feb. 1956).[13] The reprint was a replacement for a Code-disapproved story – "An Eye for an Eye", drawn by Angelo Torres[14] – but was itself also objected to because of the central character being black.[13] The story, by writer Al Feldstein and artist Joe Orlando,[14] was an allegory against race prejudice, which point was necessarily nullified if the lead character was not black.[13] Following an order by Code administrator Judge Charles Murphy to change the final panel, which depicted a black astronaut, Gaines engaged in a heated dispute with Murphy.[15] He threatened to inform the press of Murphy's objection to the story if they did not give the issue the Code Seal, causing Murphy to reverse his initial decision and allow the story to run.[13] Soon after, however, facing the severe restrictions placed upon his comics by the CCA, and with his "New Direction" titles floundering, Gaines quit comic book publishing to concentrate on Mad.[13]

In the late 1960s, the underground comics scene arose, with artists creating comics that delved into subject matter explicitly banned by the Code. Since these comics were distributed largely through unconventional channels, such as head shops, they were able to skirt the problem of mainstream distributors who were wary of carrying non-CCA-approved comics. This allowed underground comics to achieve moderate success without CCA approval.

Writer Marv Wolfman's name was briefly a point of contention between DC Comics and the CCA. In the supernatural-mystery anthology House of Secrets #83 (Jan. 1970), the book's host introduces the story "The Stuff that Dreams are Made of" as one told to him by "a wandering wolfman". (All-capitals comics lettering made no distinction between "wolfman" and "Wolfman".) The CCA rejected the story and flagged the "wolfman" reference as a violation. Fellow writer Gerry Conway explained to the CCA that the story's author was in fact named Wolfman, and asked whether it would still be in violation if that were clearly stated. The CCA agreed that it would not be, as long as Wolfman received a writer's credit on the first page of the story; this led to DC beginning to credit creators in its supernatural-mystery anthologies.[16]

The Code was revised a number of times during 1971, initially on January 28, 1971, to allow for, among other things, the sometimes "sympathetic depiction of criminal behavior... [and] corruption among public officials" ("as long as it is portrayed as exceptional and the culprit is punished"[13]) as well as permitting some criminal activities to kill law-enforcement officers and the "suggestion but not portrayal of seduction."[13] Also newly allowed were "vampires, ghouls and werewolves... when handled in the classic tradition such as Frankenstein, Dracula, and other high calibre literary works written by Edgar Allan Poe, Saki, Conan Doyle and other respected authors whose works are read in schools around the world". Zombies, lacking the requisite "literary" background, remained taboo. To get around this restriction, Marvel in the mid-1970s called the apparently deceased, mind-controlled followers of various Haitian supervillains "zuvembies".[17] This practice carried over to Marvel's superhero line: in The Avengers, when the reanimated superhero Wonder Man returns from the dead, he is referred to as a "zuvembie".[18] DC comics published their own zombie story in Swamp Thing #16 (May 1975), where the deceased rise from their graves, while a soul-devouring demon appears in Swamp Thing #15 (April 1975).

Around this time, the United States Department of Health, Education and Welfare approached Marvel Comics editor-in-chief Stan Lee to do a story about drug abuse.[13] Lee agreed and wrote a three-part Spider-Man story, portraying drug use as dangerous and unglamorous. While the Code did not specifically forbid depictions of drugs, a general clause prohibited "All elements or techniques not specifically mentioned herein, but which are contrary to the spirit and intent of the code, and are considered violations of good taste or decency".[19] The CCA had approved at least one previous story involving drugs, the premiere of Deadman in Strange Adventures #205 (Oct. 1967), which clearly depicted the title character fighting opium smugglers.[19] However, Code administrator Leonard Darvin "was ill" at the time of the Spider-Man story,[13] and acting administrator John L. Goldwater (publisher of Archie Comics) refused to grant Code approval because of the depiction of narcotics being used, regardless of the context,[13] whereas the Deadman story had depicted only a wholesale business transaction.[19]

Confident that the original government request would give him credibility, and with the approval of his publisher Martin Goodman, Lee ran the story in The Amazing Spider-Man #96–98 (May–July 1971), without CCA approval. The storyline was well received, and the CCA's argument for denying approval was deemed counterproductive. "That was the only big issue that we had" with the Code, Lee recalled in a 1998 interview:

I could understand them; they were like lawyers, people who take things literally and technically. The Code mentioned that you mustn't mention drugs and, according to their rules, they were right. So I didn't even get mad at them then. I said, 'Screw it' and just took the Code seal off for those three issues. Then we went back to the Code again. I never thought about the Code when I was writing a story, because basically I never wanted to do anything that was to my mind too violent or too sexy. I was aware that young people were reading these books, and had there not been a Code, I don't think that I would have done the stories any differently.[20]

Lee and Marvel drew criticism from DC head Carmine Infantino "for defying the code", stating that DC will not "do any drug stories unless the code is changed".[13] As a result of publicity surrounding the Department of Health, Education and Welfare's sanctioning of the storyline, however, the CCA revised the Code to permit the depiction of "narcotics or drug addiction" if presented "as a vicious habit". DC itself broached the topic in the Code-approved Green Lantern/Green Arrow #85 (Sept. 1971), with writer Denny O'Neil and artist Neal Adams beginning a story arc involving Green Arrow's teen sidekick Speedy as a heroin addict. A cover line read, "DC attacks youth's greatest problem... Drugs!"[19]

By the 1980s, greater depiction of violence had become acceptable. For example, Moon Knight #21 (July. 1982) encounters zombies, and Elvira's House of Mystery #2 (Feb. 1986) contained numerous decapitations but was still Code-approved.

A late adopter of the code was Now Comics, which began displaying the Code seal on titles released in the spring of 1989.[21]Bongo Comics, established in 1993 primarily to publish comics based upon The Simpsons television series, also chose to display the seal.

By the 2000s, advertisers no longer made decisions to advertise based on the appearance of the stamp.[22] Most new publishers to emerge during this time did not join the CCA, regardless of whether their content conformed to its standards.[22]DC Comics, Marvel Comics, and other CCA sponsors began publishing comics intended for adult audiences, without the CCA seal, and comics labeled for "mature readers" under imprints such as DC's Vertigo and Marvel's Epic Comics, and DC Comics imprints Helix and WildStorm were not submitted to the CCA.

In 2001, Marvel Comics withdrew from the CCA in favor of its own Marvel Rating System designating appropriate age groups; in 2010 Bongo Comics discontinued using the Code without any announcements regarding its abandonment.[23]

The CMAA, at some point in the 2000s, was managed by the trade-organization management firm the Kellen Company, which ceased its involvement in 2009. In 2010, some publishers, including Archie, placed the seal on its comics without submitting them to the CMAA. Archie Comics President Mike Pellerito stated that the code did not affect his company the way that it did others as "we aren't about to start stuffing bodies into refrigerators".[22]

In January 2011, DC Comics announced that it would discontinue participation, adopting a rating system similar to Marvel's.[24] The company noted that it submitted comics for approval through December 2010, but would not say to whom they were submitted.[22] A day later, Archie Comics, the only other publisher still participating in the Code, announced it also was discontinuing it,[25] rendering the Code defunct.

Inclusion of stories dealing with evil shall be used or shall be published only where the intent is to illustrate a moral issue and in no case shall evil be presented alluringly, nor so as to injure the sensibilities of the reader.

Profanity, obscenity, smut, vulgarity, or words or symbols which have acquired undesirable meanings are forbidden.

Nudity in any form is prohibited, as is indecent or undue exposure.

Suggestive and salacious illustration or suggestive posture is unacceptable.

Females shall be drawn realistically without exaggeration of any physical qualities.

Illicit sex relations are neither to be hinted at nor portrayed. Rape scenes as well as sexual abnormalities are unacceptable.

Seduction and rape shall never be shown or suggested.

Sex perversion or any inference to same is strictly forbidden.

Nudity with meretricious purpose and salacious postures shall not be permitted in the advertising of any product; clothed figures shall never be presented in such a way as to be offensive or contrary to good taste or morals.